Investigation of antioxidant compounds in commercial pomegranate molasses products using matrix-solid phase dispersion extraction coupled with HPLC

Pomegranate is a well known fruit for its unique flavor, taste and health benefits. The medicinal properties of this fruits directly associated with the phenolic content present, with great anti-oxidant potential. The research is intended to develop matrix solid phase dispersion method (MSPD) and HPLC quantification of four major anti-oxidant marker constituents (vitamin C, gallic acid, rutin & ellagic acid) in pomegranate molasses samples. The effects of several important experimental parameters like type of dispersant, sample-dispersant ratio, solvents and its volume, time of extraction were investigated. A C₁₈ column with the specification (5 µm, 250 × 4.0 mm) was used for the separation. A gradient flow of mobile phase was selected after many trials containing 0.1%, v/v solution of orthophosphoric acid and acetonitrile. The flow rate was 1.0 mL/min; and the chromatograms were recorded at 254 nm. The validation parameters, like linearity (r² = 0.9985, 0.9965, 0.9925 & 0.9986), accuracy (100.3, 99.5, 100.9 & 101.9%), intra-day precision (%RSD = 1.09, 1.02, 1.26 & 0.97), inter-day precision (%RSD = 1.32, 0.83, 1.07, & 1.15) LOD (0.07, 4.50, 0.45 & 0.40 µg/mL), LOQ (0.095, 9.50, 0.85 & 9.5 µg/mL) and robustness (% RSD = 0.92, 0.76, 0.81 & 0.83) respectively for vitamin C, gallic acid, rutin & ellagic acid, were found satisfactory as per ICH guidelines.